Almost every city has three (3) active levels. The two (2) most often viewed are the street level with its road, signs, and poles, and the upper level with its buildings, towers, and various superstructures. There is however a mostly hidden level, the subsurface level where subways, sewers, and underground utilities such as water, electrical power, communication lines, and the like reside. The number of structures and their scope in the subsurface level would likely be surprising to many.
Access to the subsurface level is usually by way of manholes that are located on paved surfaces such as roadways and parking lots. Such manholes provide ready access to underground features such as water, sewer, electrical power, communication lines, and the like to authorized personnel while restricting access to others. In addition, manholes and their covers provide safety to those operating on the street level. The weight of cars and trucks can easily be handled by a properly installed manhole and its manhole cover. Finally, manholes and their covers provide these features in a manner that is minimally disruptive to overall visual appearances.
In practice, manhole covers are usually located in frames that are set flush with a paved surface, such as a street or parking lot. This is beneficial in that the passage of vehicles, people, and the like can occur safely and with minimal intrusions. However, when such surfaces are repaved it is nearly impossible to adjust the height of the manhole cover frame to match the repaving. Drivers and pedestrians must then deal with sunken manhole covers. About the only practical alternative is a complete manhole cover frame overhaul, which can be very costly and time-consuming.
Accordingly, there exists a need for means by which manholes, their frames, and their covers can be easily adjusted in height to accommodate repaving activities or other actions which cause manholes to be improperly located.